Work vehicles may be equipped with specialized tools or work implements designed to perform tasks useful in the agricultural, forestry, construction, mining, and other industries. When powered by a rotating shaft, the work implements are referred to herein as “shaft-powered implements.” Examples of work vehicles having shaft-powered implements include cotton and sugarcane harvesters. Such harvesters may be equipped with forward-mounted row units containing movable, shaft-powered components, which pick, strip, or otherwise collect cotton fiber as the harvester travels over a field. The shaft-powered implements may be driven by an infinitely variable power source, such as a hydrostatic drive. The hydrostatic drive may include a hydrostatic motor, which is mechanically linked to the shaft-powered implements through an auxiliary power takeoff (PTO) shaft. By varying the output speed of the hydrostatic motor, the speed of the shaft-powered implements can be controlled. The ground speed of the work vehicle is further controlled utilizing a separate drivetrain, which may include a prime mover (e.g., internal combustion engine) linked to the ground wheels (or tracks) through a multi-speed transmission. Vehicle ground speed may thus be selected by varying the output speed of the engine or the gear ratio setting of the transmission, while the speed of the shaft-powered implements is independently adjusted to optimize implement performance. In the case of a cotton harvester, for example, the speed of the cotton stripper or picker units can be controlled to maximize the rate of cotton fiber collection independently of variations in the ground speed of the harvester.